Sveltejs vulnerabilities
We track 26 vulnerabilities in Sveltejs products across 3 products. 26 are rated high or critical, and none are known to be exploited. The most recent was published on November 13, 2026.
Latest Sveltejs vulnerabilities
- 7.5 High severity
kit: Inefficient Algorithmic Complexity
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. From version 2.42.0 until 3.1.1, applications using the experimental remote functions flag and a remote form function could perform quadratic synchronous work whi
- 7.5 High severity
kit: Exposure of Sensitive Information to an Unauthorized Actor
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. From version 3.0.0 until 3.1.1, the build-time server-only module guard did not treat src/params.js as a client entry point even though parameter matchers can run
- 7.5 High severity
devalue: Allocation of Resources Without Limits or Throttling
The devalue package for npm before 5.6.3 can consume excessive CPU and memory when serializing sparse arrays with uneval or stringify. An attacker who manages to get a sparse array created on the server, which mainstream wire formats do not allow, and serializ
- 7.5 High severity
devalue: Uncontrolled Resource Consumption
Sveltejs devalue before 5.9.3 contains a denial of service vulnerability that allows attackers to cause CPU amplification by supplying sparse arrays to uneval. Attackers who influence sparse values passed to uneval can force synchronous work proportional to th
- 7.5 High severity
devalue: Uncontrolled Resource Consumption
Sveltejs devalue before 5.9.3 contains a resource exhaustion vulnerability where repeated primitive strings cause quadratic expansion in the uneval function. Attackers can supply a small crafted payload that is parsed and then passed to uneval, producing a ver
- 7.5 High severity
devalue: Allocation of Resources Without Limits or Throttling
Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array seri
- 7.5 High severity
devalue: Memory Allocation with Excessive Size Value
Devalue before 5.9.3 contains a validation bypass vulnerability that allows custom ArrayBuffer revivers to skip typed-array allocation checks in the parse function. Attackers can supply very small crafted input processed by a malformed ArrayBuffer reviver to a
- 7.5 High severity
devalue: Uncaught Exception
devalue (sveltejs/devalue) 5.8.0 before 5.9.3 contains an unhandled promise rejection in stringifyAsync: when serializing multiple promises, a later promise rejecting before an earlier one settles leaves an internal rejection unhandled, even if the caller catc
- 7.5 High severity
kit: Improper Limitation of a Pathname to a Restricted Directory
SvelteKit (@sveltejs/kit) from 2.10.0 before 3.0.0 contains a path traversal vulnerability in the vite preview server on Windows that allows unauthenticated attackers to read files outside the prerendered output directory. Attackers who can reach the preview s
- 7.5 High severity
devalue: Exposure of Sensitive Information to an Unauthorized Actor
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. In versions 5.1.0 through 5.9.2, stringify and uneval functions serialize a typed array by emitting its entire backing ArrayBuffer rath
- 7.5 High severity
kit: Uncontrolled Resource Consumption
SvelteKit (@sveltejs/kit) versions >=2.49.0 and <=2.52.1 with experimental remote functions and form enabled contain a CPU exhaustion vulnerability in form deserialization. An attacker can send malformed form data to cause the server to become unresponsive whi
- 7.5 High severity
kit: Uncontrolled Resource Consumption
SvelteKit (@sveltejs/kit) versions >=2.49.0 and <=2.52.1 with experimental remote functions (experimental.remoteFunctions) and form enabled contain a memory exhaustion vulnerability in remote form deserialization. Malformed form data can cause excessive memory
- 7.5 High severity
kit: Deserialization of Untrusted Data
SvelteKit versions from 2.49.0 through 2.53.2 (fixed in 2.53.3) contain a deserialization expansion issue in the experimental form remote function. When an application enables experimental.remoteFunctions and uses the form function to process the files array w
- 7.5 High severity
devalue: Allocation of Resources Without Limits or Throttling
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. From version 5.6.3 to before version 5.8.1, devalue.parse could, due to quirks in some JavaScript engines, be convinced to allocate muc
- 7.5 High severity
svelte: Inefficient Regular Expression Complexity
Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in <svelte:element this={tag}></svelte:element>. This issue has been patched in version 5.55
- 7.5 High severity
kit: Improper Handling of Exceptional Conditions
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, redirect, when called from inside the handle server hook with a location parameter containing characters that are invalid in a HTTP header, will
- 7.5 High severity
kit: Allocation of Resources Without Limits or Throttling
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, under certain circumstances, requests could bypass the BODY_SIZE_LIMIT on SvelteKit applications running with adapter-node. This bypass does not
- 7.5 High severity
devalue: Improperly Controlled Modification of Object Prototype Attributes
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. In devalue v5.6.3 and earlier, devalue.parse and devalue.unflatten were susceptible to prototype pollution via maliciously crafted payl
- 7.5 High severity
kit: Allocation of Resources Without Limits or Throttling
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. From 2.49.0 to 2.49.4, the experimental form remote function uses a binary data format containing a representation of submitted form data. A specially-crafted pay
- 7.5 High severity
devalue: Asymmetric Resource Consumption (Amplification)
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. From 5.1.0 to 5.6.1, certain inputs can cause devalue.parse to consume excessive CPU time and/or memory, potentially leading to denial
- 7.5 High severity
devalue: Asymmetric Resource Consumption (Amplification)
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. From 5.3.0 to 5.6.1, certain inputs can cause devalue.parse to consume excessive CPU time and/or memory, potentially leading to denial
- 9.1 Critical severity
kit: Server-Side Request Forgery
SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.49.5, SvelteKit is vulnerable to a server side request forgery (SSRF) and denial of service (DoS) under certain conditions. From 2.44.0 through 2.49.4,
- 7.9 High severity
devalue: Improperly Controlled Modification of Object Prototype Attributes
Svelte devalue is a utility library. Prior to version 5.3.2, a string passed to devalue.parse could represent an object with a __proto__ property and devalue.parse does not check that an index is numeric. This could result in assigning prototypes to objects an
- 7.5 High severity
SvelteKit is a web development kit. In SvelteKit 2, sending a GET request with a body eg `{}`…
SvelteKit is a web development kit. In SvelteKit 2, sending a GET request with a body eg `{}` to a built and previewed/hosted sveltekit app throws `Request with GET/HEAD method cannot have body.` and crashes the preview/hosting. After this happens, one must ma
- 8.8 High severity
kit: Cross-Site Request Forgery
The SvelteKit framework offers developers an option to create simple REST APIs. This is done by defining a `+server.js` file, containing endpoint handlers for different HTTP methods. SvelteKit provides out-of-the-box cross-site request forgery (CSRF) protectio
- 8.8 High severity
kit: Cross-Site Request Forgery
SvelteKit is a web development framework. The SvelteKit framework offers developers an option to create simple REST APIs. This is done by defining a `+server.js` file, containing endpoint handlers for different HTTP methods. SvelteKit provides out-of-the-box c